VeriSilicon: FD-SOI & Design-Lite – A Beautiful Combination (CEO Interview)
Posted date : Jun 25, 2020

VeriSilicon provides platform-based, all-round, one-stop custom silicon services and semiconductor IP. For two years running, they’ve been the #1 Chinese IP provider and well into the Top 10 worldwide (per IPnest 2020). They’re also an FD-SOI design powerhouse. Founded in 2001, VeriSilicon first began work on FD-SOI in 2013. Now they’re headed for listing on the Shanghai STAR exchange. SOI News talked to President & CEO Dr. Wayne Wei-Ming Dai about his company’s innovative business model, and opportunities for FD-SOI.

SOI News (SN): You call the VeriSilicon business model “SiPaaS”, for Silicon Platform as a Service. Can you tell us what that means? Is it particularly well-suited to designs based on FD-SOI?

Dr. Wayne Wei-Ming Dai (WD): We see SiPaaS as the third transformation in the semiconductor industry. If you take a minute to look at the evolution, first was the IDM model of the 1960’s and 70’s, largely based in the US and Japan and driven first by the US military, then home appliances and consumer electronics. The second transformation was the foundry model, driven heavily by the PC and cellular communication, with a geographic center heavily based in Taiwan and Korea. That solved the CAPEX challenge. Now with the IoT, we solve the OPEX – operational expenses – challenge. Although 60% of our business comes from outside China, we do see particularly good opportunities for China. With AI and AIoT, there’s a lot of custom designs. You have a new model with the chip as a system, with lots of IP – but it also is much more expensive. The VeriSilicon SiPaaS model covers everything from IP to final tape-out, delivers packaged and tested parts, and that accelerates time to market and saves money.

If you consider the share of R&D expenses as a percentage of chip revenue, for leading fabless companies, they can be 20-30%, and you need to have a gross margin of 50% and higher. But if your gross margin is 40% or below, you might out of business.

The VeriSilicon model seeks to transform the design-heavy model, where designers use their own IP, to the next wave, which is design-lite. When you’ve got a design-lite model for A/IoT, you don’t need such a big team. This is the third transformation. You first saw this starting in a major way in Israel, where going to design-lite enabled fabless companies to move very quickly.

But you still need IPs, and for those working under a traditional model, we have those. In SiPaaS, we offer IP platforms. Chip design is kind of like building a house. If you want, we can just give you the kitchen – so that’s some specific IP. But we can also give you the entire house. The IPs form the solutions.

For each type of application, there are similar IPs that need to be integrated. Sets of IPs form subsystems for IoT, automotive, medical, wearables, audio, video, etc. There are no boundaries on the platforms, but each have typical elements.

In this industrial transformation, and now especially for AIoT, you’ll need many more chips in many different places. We have a lot of IP that we created organically, but we also made some major acquisitions over the years. For example, 13 years ago we bought a Dallas based DSP division from LSI Logic.

Our design-lite platform approach plays particularly well in FD-SOI, where designers want to maximize the advantages of the technology. Remember that much of the original IP for FD-SOI comes from ST or Samsung. When Samsung first licensed 28nm FD-SOI from ST, we got a whole set of 28nm FD-SOI IP from ST with modification rights. So we started to play with them. Then that IP went to Synopsys. We have modified, optimized and customized it for customers. And with GlobalFoundries’ 22nm FD-SOI, when the IP comes out, we’re the first ones invited to test it. So we focus on those IPs. We do benchmarks on ARM and others. And we’ve designed our own IPs for RF and more. We’ve done the body biasing circuits and software control, so we support design methodologies. People often ask us to show them how good FD-SOI is. So we do a lot of benchmarking. At 28 bulk, we can do apple-to-apple comparisons. And 28 bulk or 22 FD-SOI, it’s the same team, so we can do those comparisons, so they can compare the two nodes. And we’re partnering with more 3rd party IP companies – including smaller players – providing FD-SOI IP, which is great.

Our design-lite platform approach plays particularly well in #FDSOI, where designers want to maximize the advantages of the technology - @VeriSilicon CEO Wayne Dai #IoT #edgeAI #wearables Click To Tweet

SN: You have been a very vocal champion of FD-SOI. Why?

WD: We’re not against FinFET – that a really big part of our business and we’re very advanced in it. We were the first to do a tape-out on Samsung’s 7nm UV FinFET test chip and are working on 5nm. While overall we tape out over 30-50 chips a year, we are foundry neutral. But we recognize that FinFETs are not for everything: there are some things that FD-SOI does much better. Integrating RF, for example – it’s not impossible but it’s not natural in FinFET. Yes, if you’ve got a big digital chip running at high speed most of time, FinFET is better. But if you’re running high speed some of time, say around 20%, especially integrating RF, FD-SOI is better. And back biasing is impossible in FinFET. In the end, we “walk on two legs”.

SN: What do designers need to know about FD-SOI?

WD: Body biasing can sound complicated, but the thing is, you don’t play with each transistor. In theory, you can control each transistor with body bias, but in reality, you do it region by region.

With body biasing, you can dynamically make different parts of the chip behave differently. This is key. Some parts are reverse biased. Some parts are forward biased. You play with this block by block, and kick it in as-needed by software after the chip comes back.

So in IoT, for example, where it’s very serious low power, you may want to shut down certain parts when you’re not using them, while other parts always need to be on. If you choose one of our platforms, we’ve taken care of that. There may be parts you only need to bring up and run at high-speed for certain tasks. So body biasing gives you all sorts of controls. With FinFETs you can’t do that, you can just play with voltage scaling.

You can drive up the speed – the dynamic power – when needed with forward biasing. During that time, you’re not really worrying about leakage power because when the task is done you can completely shut down those parts again.

It also changes tape out. Typically designers do worst case. But you might not need to design for the worst case: you leave too much on the table. With body biasing, if you solve for typical, when the chip comes back, you can tune and make adjustments post-silicon. So you can do an aggressive tape-out, which is much more effective than starting off with a worst case.

True, if you sign off worst case, your chip can always run very fast, but sometimes you don’t need that. And in order to solve for worst-case, you put in a lot of buffers or whatever for timing closure, which is unnecessary effort. What’s more, for different applications, the worst case can be different: some applications may need some higher speeds and sometimes less. If you solve for typical, then depending on the application you can software-tune the device. In the past, you never had that kind of thing.

With body biasing in FD-SOI, you can solve for typical, so you can save a lot of area and a lot of design cycle in terms of timing closure, in terms of use of buffers.

If silicon comes back, and it’s missing something – say you need it to go a little faster – I’ve done body biasing, so I adjust the timing. Most times it’s probably ok, it’s good enough. Of course, some applications you need some combination of fast and slow, and you can leverage the body-biasing post silicon to change what’s fast and what’s slow on the fly.

Like in wearables, power is very critical – some parts are always on, and some parts are sometimes on. For the parts that are always on, you need to reduce the leakage, and you do that with reverse body biasing.

For other parts, you bring them up and you run as fast as you can for a short period of time – in this case leakage isn’t as important because most of the time it’s shut down. But dynamic power is important. High performance is important. For that part you need forward biasing.

With different parts of the chip, you can play with different things. Before, you had to do this before tape-out, and sometimes had to do worst-case, which should never happen: you leave too much margin on the table, because after silicon you couldn’t do anything. But now with body biasing in FD-SOI, you have the capability – you don’t need to do worst case – if needed you can always adjust. And for different applications in the chip, you might need a different kind of operating frequency, right? So you can create different chips from the same chip.

With body biasing, you can always tune to whatever you want. If I’m short of something, I can do some body biasing bring up the speed. Now that’s different from voltage scaling. You cannot dynamically achieve voltage scaling. You might have two voltages – one’s high, one’s low. But you cannot continuously change. In FD-SOI the same die maybe has different applications with different performance requirements, so we don’t need to do worst case design. They can come up with different performance chips in the same silicon.

SN: What do you see as the drivers?

WD: IoT, AIoT and automotive. Also RF, mmWave and connectivity. And at the edge, where you need very low power. FinFET and FD-SOI both solve the leakage problem. But if you need sleep mode most of the time and high performance 20% of the time, it is more energy efficient to use FD-SOI. There are a lot of applications in this category. In 12nm FD-SOI, you’ll reach almost the same performance as 7nm FinFET at 14nm cost.

#FinFET & #FDSOI both solve the leakage problem. But if you need sleep mode most of the time and high performance 20% of the time, it is more energy efficient to use FD-SOI /@VeriSilicon CEO #edgecomputing Click To Tweet

You’ve seen some stagnation of IoT at the 40/55nm process nodes because at those nodes the performance was not as good as expected. You needed two AA batteries. The value of the IoT data was not generated, collected or analyzed. What you need is AI at the edge to pre-process the raw data so you lower network capacity requirements. AI at the edge is a great opportunity for FD-SOI.

SN: How do you see the role of the SOI Consortium?

WD: We work with the consortium for these big forums; in particular VeriSilicon co-founded and has now co-sponsored the Shanghai FD-SOI Forum for seven years. They’re the most visible and high quality. The consortium knows the people that need to know each other. There are a lot of meetings during these events, and a lot of deals are sealed; one signature event is the river dinner cruise where “everyone is on the same boat”.

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Related VeriSilicon press releases:

VeriSilicon Releases Most Advanced FD-SOI Design IP Platform on GlobalFoundries 22FDX for Edge AI and IoT Applications (2019-10-24). The VeriSilicon 22FDX IP Platform includes over 30 low-power, low-leakage and high-density memory compiler IPs and various key mixed signal IPs. VeriSilicon provides a one-stop silicon design service to customers designing for AIoT with mature IPs to shorten custom design cycles and reduce their R&D costs. FD-SOI Body-Bias technology allows the user to adjust device threshold even after silicon is manufactured: it can enable dynamic tuning between High-Performance and Low-Power, and enhance the design flexibility without extra cost.

Advanced ATSC 3.0 Chip Launched for Mobile and Broadcast Applications (2019-01-08). The demodulator SoC was designed and developed by Saankhya Labs with ASIC turnkey design and manufacturing services from VeriSilicon, using Samsung Foundry’s state of the art 28FDS (its Fully Depleted SOI process technology), chosen for its unique low power capabilities offered by the back bias option. (See more in-depth coverage on this announcement from SOI News here.)

VeriSilicon Announces Ultra Low Power BLE 5.0 RF IP based on GLOBALFOUNDRIES 22FDX FD-SOI Process for IoT Applications (2018-11-01). The IP includes a transceiver that is compliant with the BLE 5.0 specification and supports GFSK modulation and demodulation. The silicon measurement shows that the sensitivity can be tested up to -98dBm with less than 7mW power dissipation in typical conditions. It largely improves battery life for low power IoT applications. In addition, the RF transceiver saves 40% area compared to a similar implementation on 55nm bulk CMOS. Besides the RF transceiver, this IP integrates on-chip balun, TX/RX switch and 32K RC OSC driver to save the BOM. Moreover, high efficiency DC/DC and LDOs are also available for power management. “Wearable and IoT markets especially the wireless earplug market are growing rapidly, and it will surge through consumer use, hearing aids, personal care and other industrial applications.” said Dr. Wayne Dai, Founder, Chairman, President and CEO of VeriSilicon. “By taking advantage of integrated RF capabilities of FD-SOI, in particular GF’s 22FDX, our BLE 5.0 RF IP will significantly reduce the system cost and greatly boost the growth momentum of wearable products such as wireless earplugs.”

GlobalFoundries and VeriSilicon to Enable Single-Chip Solution for Next-Gen IoT Networks (2017-07-13). The integrated solution leverages GF’s 22FDX technology to decrease power, area, and cost for NB-IoT and LTE-M applications.

VeriSilicon’s Artificial Intelligence Engine Delivers Multi-Sensory Experiences in NXP’s i.MX 8 Flagship Applications Processor. (2017-06-08).



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